CN109280023A - A kind of caprolactam continuous crystallisation purification process - Google Patents
A kind of caprolactam continuous crystallisation purification process Download PDFInfo
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- CN109280023A CN109280023A CN201811468932.3A CN201811468932A CN109280023A CN 109280023 A CN109280023 A CN 109280023A CN 201811468932 A CN201811468932 A CN 201811468932A CN 109280023 A CN109280023 A CN 109280023A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/16—Separation or purification
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D223/08—Oxygen atoms
- C07D223/10—Oxygen atoms attached in position 2
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Abstract
The present invention provides a kind of caprolactam continuous crystallisation purification process, comprising the following steps: liquid caprolactam crude product is configured to the caprolactam water solution that mass concentration is 75 ~ 85%；Above-mentioned caprolactam water solution is subjected to multi-stage vacuum, crystallization is evaporated under reduced pressure, obtains the crystallized stock of 56 ~ 70% caprolactam crystal precipitation；Above-mentioned crystallized stock is centrifuged, centrifuge mother liquor and caprolactam crystal are obtained；Caprolactam crystal is dried to get caprolactam solid product is arrived.The present invention can effectively avoid knot wall phenomenon, ensure to crystallize the continuity of production, simultaneously, it is ensured that temperature equalization in crystallizing tank, and pass through multistage crystallization mode, ensure the high homogeneity of caprolactam crystal form, product quality, qualification rate and quality stability are improved, energy consumption is reduced, and is controlled easy, easily operated, operating cost is low.
Description
Technical field
The present invention relates to a kind of organic matter crystallization purifications, and in particular to a kind of caprolactam continuous crystallisation purifying side
Method.
Background technique
Caprolactam (C6H11NO), white powder or crystalline solid, soluble easily in water and chlorinated solvent, petroleum hydrocarbon, ethyl alcohol, second
When heated polymerization reaction easily occurs for the organic reagents such as ether, acetone, benzene.Caprolactam is a kind of important Organic Chemicals, main
Wanting purposes is that polyamide slice (commonly referred to as nylon-6 slice or polyamide fibre -6 are sliced) is generated by polymerization, can be further processed
It is a small amount of for producing lysine at nylon fibre, engineering plastics, plastic film.Caprolactam also can be directly used for spinning or straight
It connects and does MC nylon through moulding by casting, MC nylon products have weight as one of engineering plastics, " brilliant to mould Dai Gang, performance "
Gently, a variety of special performances such as intensity height, self-lubricating, wear-resisting, anti-corrosion, insulation, purposes is extremely extensive, almost spreads over all industry
Field.
When the aggregated production downstream product of caprolactam, impurity content therein will affect the degree of polymerization of downstream product, because
The fewer the impurity content of this caprolactam finished product the better.Since preparing process of caprolactam is complex, in caprolactam crude product
Impurity various types, therefore the polishing purification process of caprolactam is extremely important.Conventional polishing purification method includes: chemical essence
(potassium permanganate oxidation, catalytic hydrogenation etc.) method, extraction, recrystallization method, ion-exchange-resin process, vacuum distillation method etc. is made, is
High purity product is obtained, industrial is usually that combination several method carries out joint purification.
Currently, preparing the refining methd of caprolactam using cyclohexanone oxamidinating, Beckmann rearrangement method are as follows: Beckmann rearrangement
Terminate amide oil obtained by benzene extraction, water back extraction, ion exchange, the processes such as hydrogen, evaporation, distillation is added to obtain liquid in oneself
Amide oil, this process for refining there are long flow path, process is complicated, solvent distillation energy consumption is high, ion exchange waste water discharge amount is big, environmental protection
The problems such as pressure is big, and finally obtained product caprolactam is only liquid, needs high-temperature storage, unstable quality, qualification rate
The problems such as low.
The patent application of 107778244 A of Publication No. CN discloses " a method of purification purification caprolactam ",
It is crystallized using two-stage low temperature, obtains caprolactam solid, crystalline mother solution obtains liquid caprolactam after distilling, while crystallizing mother
Liquid is used through evaporation removal of impurities rear enclosure.The invention method using two-stage crystallization mode and distillation of arranging in pairs or groups, evaporation technique than traditional extraction,
Back extraction, ion exchange plus hydrogen, low energy consumption for distillation evaporation purification techniques, and process is short.But the crystal in crystallization process has
Shi Huijie wall, knot wall is more and more thicker, influences heat-transfer effect, causes production that cannot be carried out continuously, influences normally to produce；And formed
Grain size is different, and particle size distribution is wide, and the uniform effect of crystal form is poor, the unstable quality of product, and product qualified rate is low.For
The energy consumption in caprolactam crystallization process is further decreased, knot wall is solved the problems, such as, improves the uniformity of caprolactam crystal form, surely
Fixed output quota quality, improves the qualification rate of the finished product, it is necessary to improve to the crystallization purifying technique of caprolactam.
Summary of the invention
It is an object of the invention to provide a kind of caprolactam continuous crystallisation purification process, to solve existing method energy consumption
High, the problems such as crystal form uniformity is poor, unstable product quality, low product qualified rate.
The object of the present invention is achieved like this:
A kind of caprolactam continuous crystallisation purification process, comprising the following steps:
(1) preparation of caprolactam solution
Liquid caprolactam crude product is configured to the caprolactam water solution that mass concentration is 75 ~ 85%；
(2) level-one vacuum decompression evaporative crystallization
The caprolactam water solution that the mass concentration that step (1) obtains is 75 ~ 85% is added in first degree crystalline tank, to level-one
Crystallizing tank is vacuumized, and the rate of temperature fall controlled in first degree crystalline tank is not higher than 0.2 DEG C/min, is evaporated under reduced pressure out 14 ~ 18%
Water, maintenance speed of agitator are 50 ~ 80rpm, and residence time of material is 30 ~ 60min, obtain primary crystallization material；The crystallized stock
In, the quality of caprolactam crystal accounts for 11 ~ 26% of the caprolactam total amount in the caprolactam water solution of step (1).
(3) crystallization is evaporated under reduced pressure in secondary vacuum
Primary crystallization material obtained in step (2) is sent into secondary crystallization tank, secondary crystallization tank is vacuumized, is controlled
Rate of temperature fall in secondary crystallization tank is not higher than 0.2 DEG C/min, and 19 ~ 23% water is evaporated under reduced pressure out, maintain speed of agitator be 50 ~
80rpm, residence time of material are 30 ~ 60min, obtain secondary crystallization material；In the crystallized stock, the quality of caprolactam crystal
Account for 23 ~ 40% of the caprolactam total amount in the caprolactam water solution of step (1).
(4) three-level vacuum decompression evaporative crystallization
Secondary crystallization material obtained in step (3) is sent into three-level crystallizing tank, three-level crystallizing tank is vacuumized, is controlled
Rate of temperature fall in three-level crystallizing tank is not higher than 0.2 DEG C/min, and 14 ~ 18% water is evaporated under reduced pressure out, maintain speed of agitator be 50 ~
80rpm, residence time of material are 30 ~ 60min, obtain crystallized stock three times；In the crystallized stock, the quality of caprolactam crystal
Account for 56 ~ 70% of the caprolactam total amount in the caprolactam water solution of step (1).
(5) it by crystallized stock is centrifuged three times obtained in step (4), obtains centrifuge mother liquor and caprolactam is brilliant
Body；Caprolactam crystal is dried to get caprolactam solid product is arrived.
The invention also includes following steps:
(6) centrifuge mother liquor obtained in step (5) is sent into mother liquor crystallization tank, mother liquor crystallization tank is vacuumized, control is female
Rate of temperature fall in liquid crystallizing tank is not higher than 0.2 DEG C/min, is down to 5 ~ 10 DEG C to temperature, the water of half is evaporated under reduced pressure out, obtains
There is the crystallized stock of caprolactam precipitation, it is total to account for caprolactam in centrifuge mother liquor for the quality of caprolactam crystal in the crystallized stock
The 15 ~ 55% of amount.
(7) crystallized stock obtained in step (6) is centrifuged, obtains secondary centrifuging mother liquor and caprolactam is brilliant
Body, secondary centrifuging mother liquor are sent into the preparation process of caprolactam crude product (such as evaporation removing low boiling impurity process) and are applied,
Caprolactam crystal is dried together with the caprolactam crystal in step (5).
Liquid caprolactam crude product in the step (1) be the amide oil that obtains Beckmann rearrangement through desulfurization ammonium, steam
High-boiling-point impurity is distilled off in hair removing low boiling impurity, obtains gaseous state caprolactam, then gaseous state caprolactam condensed and
?.
The temperature of caprolactam water solution in the step (1) is 40 ~ 43 DEG C.
It is equipped with insulating layer on the outer wall of each crystallizing tank, is equipped with rabbling mechanism in each crystallizing tank.
The water being evaporated under reduced pressure out in each crystallizing tank is back to use in step (1), the preparation for caprolactam solution.
Rate of temperature fall in each crystallizing tank is preferably 0.1 ~ 0.2 DEG C/min.
Process flow diagram of the invention is shown in Fig. 1.
The present invention makes the slow reduction of temperature-controllable using the evaporation rate that mode controls water in crystallizing tank is vacuumized, and protects
The phenomenon that card crystallization tank skin nodeless mesh is assembled, and " crystallization knot wall " is avoided occurs.Compared with traditional jacket type temperature control method, this hair
Bright method can effectively avoid " crystallization knot wall " phenomenon, it is ensured that the stability of product quality improves Qualified Products Rate.
The present invention uses multistage crystallization mode, and water is removed by way of vacuum distillation, and it is molten to reduce caprolactam in water removal
While solution amount, heat is taken away by the vaporization of water, gradually reduces temperature, and then reduces the solubility of caprolactam, control
The speed of growth of caprolactam crystal grain, further control caprolactam crystal grain distribution, it is ensured that caprolactam crystal form it is equal
One property, improves the quality of caprolactam product.
Caprolactam product prepared by the method for the present invention in light absorption value≤0.04 of 290nm wavelength, basicity≤
0.08mmol/kg, potassium permanganate absorption value≤4, cyclohexanone oxime content≤15mg/kg, 50% aqueous solution coloration≤2Hazen, iron
Content≤0.2mg/kg meets high-class product index in GB/T13254-2017.More in easy polymerization, downstream production can be improved in downstream product
The quality of product.Moreover, caprolactam crystal purity is high, washing is easier when subsequent centrifugation, and drying control is also easy；Obtain oneself
Lactams solid product good quality and stabilization, convenient for storage and transport.
Low energy consumption for purification process of the invention, compared with traditional caprolactam refining purifying process, can reduce by 40 ~ 60%
Energy consumption, operating cost is low.
Detailed description of the invention
Fig. 1 is process flow diagram of the invention.
Specific embodiment
Below with reference to embodiment, the present invention is further elaborated, the process being not described in detail in the following embodiments and
Method is conventional method well known in the art, and raw materials used or reagent is unless otherwise stated commercially available product in embodiment, can be led to
Commercial channel is crossed to buy.
The outer wall of used each crystallizing tank is equipped with insulating layer in various embodiments of the present invention, and is provided with blender
Structure.
Embodiment 1
(1) caprolactam solution is prepared
The amide oil that Beckmann rearrangement obtains through desulfurization ammonium, evaporation removing low boiling impurity, is distilled off high-boiling-point impurity, obtains
To gaseous state caprolactam, liquid caprolactam crude product is obtained after the condensation of gaseous state caprolactam, liquid caprolactam crude product is prepared
The caprolactam water solution for being 75% at mass concentration, the temperature of the aqueous solution are 41 DEG C；
(2) level-one vacuum decompression evaporative crystallization
The caprolactam water solution that the mass concentration that step (1) is obtained is 75% is added in first degree crystalline tank, to first degree crystalline tank
It is vacuumized, controlling the rate of temperature fall in first degree crystalline tank is 0.2 DEG C/min, and maintenance speed of agitator is 50rpm, and material is in tank
After interior stop 30min, temperature is reduced to 35 DEG C, and part water is evaporated in temperature-fall period, obtains the one of caprolactam crystal precipitation
Grade crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts for caprolactam in the caprolactam water solution of step (1)
The 13.3% of total amount；
(3) crystallization is evaporated under reduced pressure in secondary vacuum
The first degree crystalline material (comprising crystal and solution) that step (2) is obtained is sent into secondary crystallization tank, to secondary crystallization tank
It is vacuumized, controlling the rate of temperature fall in secondary crystallization tank is 0.2 DEG C/min, and maintenance speed of agitator is 50rpm, and material is in tank
After interior stop 30min, temperature is down to 29 DEG C, and part water is evaporated in temperature-fall period, obtains the two of caprolactam crystal precipitation
Grade crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts for caprolactam in the caprolactam water solution of step (1)
The 26.7% of total amount；
(4) three-level vacuum decompression evaporative crystallization
The secondary crystallization material (comprising crystal and solution) that step (3) is obtained is sent into three-level crystallizing tank, to three-level crystallizing tank
It is vacuumized, controlling the rate of temperature fall in three-level crystallizing tank is 0.2 DEG C/min, and maintenance speed of agitator is 50rpm, and material is in tank
After interior stop 30min, temperature is down to 23 DEG C, and part water is evaporated in temperature-fall period, obtains the three of caprolactam crystal precipitation
Grade crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts for caprolactam in the caprolactam water solution of step (1)
The 64% of total amount；
(5) primary centrifuge separation
The three-level crystallized stock that step (4) is obtained is sent into centrifuge, is centrifuged, and obtains in a centrifuge mother liquor and oneself
Amide crystal；
(6) mother liquor vacuum decompression evaporative crystallization
The centrifuge mother liquor that step (5) is obtained is sent into mother liquor crystallization tank, vacuumizes to mother liquor crystallization tank, controls mother liquor
Rate of temperature fall in crystallizing tank is 0.2 DEG C/min, and maintenance speed of agitator is 50rpm, part water is evaporated in temperature-fall period, to temperature
Degree is down to 8 DEG C, there is the precipitation of caprolactam crystal, and the quality of caprolactam crystal is 25% of caprolactam total amount in centrifuge mother liquor；
(7) secondary centrifuging separates
Liquid in step (6) in mother liquor crystallization tank is sent into centrifuge and carries out secondary centrifuging separation, obtains secondary centrifuging mother liquor
And caprolactam crystal, the evaporation process that secondary centrifuging mother liquor is sent into step (1) are applied；
(8) crystal is dry
Caprolactam crystal obtained in step (5) and step (7) is dried, the caprolactam of purity 99.993% is obtained
Solid product.
Effluent reuse is evaporated under reduced pressure in the above process, in step (2), (3), (4) and (6) in step (1), for preparing
Caprolactam water solution.
Embodiment 2
(1) caprolactam solution is prepared
The amide oil that Beckmann rearrangement obtains through desulfurization ammonium, evaporation removing low boiling impurity, is distilled off high-boiling-point impurity, obtains
To gaseous state caprolactam, liquid caprolactam crude product is obtained after the condensation of gaseous state caprolactam, liquid caprolactam crude product is prepared
The caprolactam water solution for being 85% at mass concentration, the temperature of the aqueous solution are 43 DEG C；
(2) level-one vacuum decompression evaporative crystallization
The caprolactam water solution that the mass concentration that step (1) is obtained is 85% is added in first degree crystalline tank, to first degree crystalline tank
It is vacuumized, controlling the rate of temperature fall in first degree crystalline tank is 0.1 DEG C/min, and maintenance speed of agitator is 80rpm, and material is in tank
After interior stop 60min, temperature is reduced to 37 DEG C, and part water is evaporated in temperature-fall period, obtains the one of caprolactam crystal precipitation
Grade crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts for caprolactam in the caprolactam water solution of step (1)
The 21.2% of total amount；
(3) crystallization is evaporated under reduced pressure in secondary vacuum
The first degree crystalline material (comprising crystal and solution) that step (2) is obtained is sent into secondary crystallization tank, to secondary crystallization tank
It is vacuumized, controlling the rate of temperature fall in first degree crystalline tank is 0.1 DEG C/min, and maintenance speed of agitator is 80rpm, and material is in tank
After interior stop 60min, temperature is reduced to 31 DEG C, and part water is evaporated in temperature-fall period, obtains the two of caprolactam crystal precipitation
Grade crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts for caprolactam in the caprolactam water solution of step (1)
The 30.6% of total amount；
(4) three-level vacuum decompression evaporative crystallization
The secondary crystallization material (comprising crystal and solution) that step (3) is obtained is sent into three-level crystallizing tank, to three-level crystallizing tank
It is vacuumized, controlling the rate of temperature fall in three-level crystallizing tank is 0.1 DEG C/min, and maintenance speed of agitator is 80rpm, and material is in tank
After interior stop 60min, temperature is down to 25 DEG C, and part water is evaporated in temperature-fall period, obtains the three of caprolactam crystal precipitation
Grade crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts for caprolactam in the caprolactam water solution of step (1)
The 60% of total amount；
(5) primary centrifuge separation
The three-level crystallized stock that step (4) is obtained is sent into centrifuge, is centrifuged, and obtains in a centrifuge mother liquor and oneself
Amide crystal；
(6) mother liquor vacuum decompression evaporative crystallization
The centrifuge mother liquor that step (5) is obtained is sent into mother liquor crystallization tank, vacuumizes to mother liquor crystallization tank, controls mother liquor
Rate of temperature fall in crystallizing tank is 0.2 DEG C/min, and maintenance speed of agitator is 80rpm, part water is evaporated in temperature-fall period, to temperature
Degree is down to 10 DEG C, there is the precipitation of caprolactam crystal, and the quality of caprolactam crystal is caprolactam total amount in centrifuge mother liquor
40%；
(7) secondary centrifuging separates
Liquid in step (6) in mother liquor crystallization tank is sent into centrifuge and carries out secondary centrifuging separation, obtains secondary centrifuging mother liquor
And caprolactam crystal, secondary centrifuging mother liquor are sent into evaporation process in step (1) and are applied；
(8) crystal is dry
Caprolactam crystal obtained in step (5) and step (7) is dried, the caprolactam of purity 99.993% is obtained
Solid product.
Effluent reuse is evaporated under reduced pressure in the above process, in step (2), (3), (4) and (6) in step (1), for preparing
Caprolactam water solution.
Embodiment 3
(1) caprolactam solution is prepared
The amide oil that Beckmann rearrangement obtains through desulfurization ammonium, evaporation removing low boiling impurity, is distilled off high-boiling-point impurity, obtains
To gaseous state caprolactam, liquid caprolactam crude product is obtained after the condensation of gaseous state caprolactam, liquid caprolactam crude product is prepared
The caprolactam water solution for being 80% at mass concentration, the temperature of the aqueous solution are 40 DEG C；
(2) level-one vacuum decompression evaporative crystallization
The caprolactam water solution that the mass concentration that step (1) is obtained is 80% is added in first degree crystalline tank, to first degree crystalline tank
It is vacuumized, controlling the rate of temperature fall in first degree crystalline tank is 0.15 DEG C/min, and maintenance speed of agitator is 65rpm, and material exists
After stopping 40min in tank, temperature is reduced to 34 DEG C, and part water is evaporated in temperature-fall period, obtains the precipitation of caprolactam crystal
First degree crystalline material, in the crystallized stock, the quality of caprolactam crystal accounts in the caprolactam water solution of step (1) acyl in oneself
The 18.8% of amine total amount；
(3) crystallization is evaporated under reduced pressure in secondary vacuum
The first degree crystalline material (comprising crystal and solution) that step (2) is obtained is sent into secondary crystallization tank, to secondary crystallization tank
It is vacuumized, controlling the rate of temperature fall in first degree crystalline tank is 0.15 DEG C/min, and maintenance speed of agitator is 65rpm, and material exists
After stopping 40min in tank, temperature is reduced to 28 DEG C, and part water is evaporated in temperature-fall period, obtains the precipitation of caprolactam crystal
Secondary crystallization material, in the crystallized stock, the quality of caprolactam crystal accounts in the caprolactam water solution of step (1) acyl in oneself
The 31.3% of amine total amount；
(4) three-level vacuum decompression evaporative crystallization
The secondary crystallization material (comprising crystal and solution) that step (3) is obtained is sent into three-level crystallizing tank, to three-level crystallizing tank
It is vacuumized, controlling the rate of temperature fall in first degree crystalline tank is 0.15 DEG C/min, and maintenance speed of agitator is 65rpm, and material exists
After stopping 40min in tank, temperature is reduced to 22 DEG C, and part water is evaporated in temperature-fall period, obtains the precipitation of caprolactam crystal
Three-level crystallized stock, in the crystallized stock, the quality of caprolactam crystal accounts in the caprolactam water solution of step (1) acyl in oneself
The 62.5% of amine total amount；
(5) primary centrifuge separation
The three-level crystallized stock that step (4) is obtained is sent into centrifuge, is centrifuged, and obtains in a centrifuge mother liquor and oneself
Amide crystal；
(6) mother liquor vacuum decompression evaporative crystallization
The centrifuge mother liquor that step (5) is obtained is sent into mother liquor crystallization tank, vacuumizes to mother liquor crystallization tank, controls mother liquor
Rate of temperature fall in crystallizing tank is 0.2 DEG C/min, and maintenance speed of agitator is 65rpm, part water is evaporated in temperature-fall period, to temperature
Degree is down to 5 DEG C, has the precipitation of caprolactam crystal, the quality of caprolactam crystal is 30% of caprolactam total amount in centrifuge mother liquor；
(7) secondary centrifuging separates
Liquid in step (6) in mother liquor crystallization tank is sent into centrifuge and carries out secondary centrifuging separation, obtains secondary centrifuging mother liquor
And caprolactam crystal, the evaporation process that secondary centrifuging mother liquor is sent into step (1) are applied；
(8) crystal is dry
Caprolactam crystal obtained in step (5) and step (7) is dried, the caprolactam of purity 99.993% is obtained
Solid product.
Effluent reuse is evaporated under reduced pressure in the above process, in step (2), (3), (4) and (6) in step (1), for preparing
Caprolactam water solution.
Comparative example 1
Referring to embodiment 1, the difference is that, the rate of temperature fall in crystallizing tanks at different levels is 0.22 DEG C/min.Finally obtained product is brilliant
Grain is not of uniform size, and size distribution is uneven, range is wide, and the uniform effect of crystal form is poor, and the index of high-class product in new national standard is not achieved, is used for
When the preparation of downstream product, the inferior quality of gained downstream product.
To embodiment 1-3 products obtained therefrom according to industrial caprolactam product new standard GB/T13254-2017(2018 5
Month 1 day implement) in project detected, test result see the table below.As can be seen from the table, prepared by the present invention in oneself
Amide products have reached or even surmount the high-class product index in GB/T13254-2017.
Claims (9)
1. a kind of caprolactam continuous crystallisation purification process, which comprises the following steps:
(1) preparation of caprolactam solution
Liquid caprolactam crude product is configured to the caprolactam water solution that mass concentration is 75 ~ 85%；
(2) level-one vacuum decompression evaporative crystallization
The caprolactam water solution that the mass concentration that step (1) obtains is 75 ~ 85% is added in first degree crystalline tank, to level-one
Crystallizing tank is vacuumized, and the rate of temperature fall controlled in first degree crystalline tank is not higher than 0.2 DEG C/min, and part water is evaporated under reduced pressure out,
Maintenance speed of agitator is 50 ~ 80rpm, and residence time of material is 30 ~ 60min, obtains primary crystallization material；
(3) crystallization is evaporated under reduced pressure in secondary vacuum
Primary crystallization material obtained in step (2) is sent into secondary crystallization tank, secondary crystallization tank is vacuumized, is controlled
Rate of temperature fall in secondary crystallization tank is not higher than 0.2 DEG C/min, and part water is evaporated under reduced pressure out, maintain speed of agitator be 50 ~
80rpm, residence time of material are 30 ~ 60min, obtain secondary crystallization material；
(4) three-level vacuum decompression evaporative crystallization
Secondary crystallization material obtained in step (3) is sent into three-level crystallizing tank, three-level crystallizing tank is vacuumized, is controlled
Rate of temperature fall in three-level crystallizing tank is not higher than 0.2 DEG C/min, and part water is evaporated under reduced pressure out, maintain speed of agitator be 50 ~
80rpm, residence time of material are 30 ~ 60min, obtain crystallized stock three times；
(5) by crystallized stock is centrifuged three times obtained in step (4), centrifuge mother liquor and caprolactam crystal are obtained；It will
Caprolactam crystal is dried to arrive caprolactam solid product.
2. caprolactam continuous crystallisation purification process according to claim 1, which is characterized in that further comprising the steps of:
(6) centrifuge mother liquor obtained in step (5) is sent into mother liquor crystallization tank, mother liquor crystallization tank is vacuumized, control is female
Rate of temperature fall in liquid crystallizing tank is not higher than 0.2 DEG C/min, is down to 5 ~ 10 DEG C to temperature, obtains the crystallization of caprolactam precipitation
Material；
(7) crystallized stock obtained in step (6) is centrifuged, obtains secondary centrifuging mother liquor and caprolactam crystal,
Secondary centrifuging mother liquor is sent into the preparation process of caprolactam crude product and is applied, acyl in oneself in caprolactam crystal and step (5)
Amine crystal is dried together.
3. caprolactam continuous crystallisation purification process according to claim 1, which is characterized in that in the step (1)
Liquid caprolactam crude product is that the amide oil for obtaining Beckmann rearrangement is removed through desulfurization ammonium, evaporation removing low boiling impurity, distillation
High-boiling-point impurity is removed, obtains gaseous state caprolactam, then gaseous state caprolactam is condensed and is obtained.
4. caprolactam continuous crystallisation purification process according to claim 1, which is characterized in that in the step (1)
The temperature of caprolactam water solution is 40 ~ 43 DEG C.
5. caprolactam continuous crystallisation purification process according to claim 1 or 2, which is characterized in that in each crystallizing tank
It is equipped with insulating layer on outer wall, is equipped with rabbling mechanism in each crystallizing tank.
6. caprolactam continuous crystallisation purification process according to claim 1 or 2, which is characterized in that subtract in each crystallizing tank
The water evaporated is pressed to be back to use in step (1).
7. caprolactam continuous crystallisation purification process according to claim 1 or 2, which is characterized in that in each crystallizing tank
Rate of temperature fall is 0.1 ~ 0.2 DEG C/min.
8. caprolactam continuous crystallisation purification process according to claim 1, which is characterized in that step (4) obtain three
The quality of caprolactam crystal accounts for 56 ~ 70% of caprolactam total amount in step (1) caprolactam water solution in secondary crystallized stock.
9. caprolactam continuous crystallisation purification process according to claim 2, which is characterized in that the knot that step (6) obtains
The quality of caprolactam crystal accounts for 15 ~ 55% of caprolactam total amount in centrifuge mother liquor in brilliant material.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110483330A (en) * | 2019-09-18 | 2019-11-22 | 湖南百利工程科技股份有限公司 | A kind of cyclohexanone oxime crystal refining method and its application in caprolactam preparation |
| CN111170916A (en) * | 2020-01-20 | 2020-05-19 | 福建中锦新材料有限公司 | Continuous crystallization and purification method of caprolactam |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011078668A1 (en) * | 2009-12-22 | 2011-06-30 | Dsm Ip Assets B.V. | The preparation of caprolactam from 6-amino caproic acid obtained in a fermentation process |
| CN201930572U (en) * | 2010-12-31 | 2011-08-17 | 森田化工(张家港)有限公司 | Continuous vacuum cooling crystallizing device |
| CN203677988U (en) * | 2014-02-19 | 2014-07-02 | 赵济彦 | Crystallization device |
| CN107778244A (en) * | 2017-12-07 | 2018-03-09 | 陕西科原环保节能科技有限公司 | A kind of method of refined purification caprolactam |
| CN108358823A (en) * | 2018-04-20 | 2018-08-03 | 陕西宏元化工技术有限公司 | A method of with organic solvent crystal refining caprolactam |
-
2018
- 2018-12-04 CN CN201811468932.3A patent/CN109280023B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011078668A1 (en) * | 2009-12-22 | 2011-06-30 | Dsm Ip Assets B.V. | The preparation of caprolactam from 6-amino caproic acid obtained in a fermentation process |
| CN201930572U (en) * | 2010-12-31 | 2011-08-17 | 森田化工(张家港)有限公司 | Continuous vacuum cooling crystallizing device |
| CN203677988U (en) * | 2014-02-19 | 2014-07-02 | 赵济彦 | Crystallization device |
| CN107778244A (en) * | 2017-12-07 | 2018-03-09 | 陕西科原环保节能科技有限公司 | A kind of method of refined purification caprolactam |
| CN108358823A (en) * | 2018-04-20 | 2018-08-03 | 陕西宏元化工技术有限公司 | A method of with organic solvent crystal refining caprolactam |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110483330A (en) * | 2019-09-18 | 2019-11-22 | 湖南百利工程科技股份有限公司 | A kind of cyclohexanone oxime crystal refining method and its application in caprolactam preparation |
| CN110483330B (en) * | 2019-09-18 | 2023-12-01 | 湖南百利工程科技股份有限公司 | Cyclohexanone oxime crystallization refining method and application thereof in caprolactam preparation |
| CN111170916A (en) * | 2020-01-20 | 2020-05-19 | 福建中锦新材料有限公司 | Continuous crystallization and purification method of caprolactam |
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| CN109280023B (en) | 2020-06-12 |
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